The MoNaUhr project, funded under grant 16ES0952 by the German Federal Ministry of Education and Research, ran from 1 March 2019 to 28 February 2022 and was extended to 31 August 2022. The project partner was ADZ Nagano GmbH, a sensor‑technology company, with project leadership by Hannes Georgi and co‑reporting by Uwe Kostudis. The aim was to develop a multifunctional nano‑electronic warning system for environmental data that could be integrated into a mechanical watch. The novelty lay in combining quantum‑dot (QD) layers for electroluminescence and ultraviolet detection, photon‑to‑electric conversion, and a miniature energy‑harvesting and storage system that would power the watch’s electronics via the lünette.
The technical work focused on a feasibility study of the required components. Micro‑generators were identified as the primary source of mechanical energy. Two variants were designed: a 6.4 mm rotor‑stator assembly and a 4.6 mm version that required a gear drive. Both used a flex‑PCB to reduce the stator depth and were intended to be driven synchronously by up to four units. To test the generators, an Arduino‑controlled stepper motor was used to provide a reproducible rotation profile, and a laser‑based measurement device (UNI‑T UT372) measured the actual speed. The tests revealed that the generators produced very low currents and voltages, which posed a challenge for efficient energy capture.
Energy harvesting was addressed by selecting the LTC3109 power‑management IC, which can step up micro‑volt inputs to a usable level. Test kits for the LTC3109 were procured and integrated into a prototype harvester. The harvested energy was stored in a solid‑state battery (CeraCharge) that could be charged from the micro‑generator output. The combination of the harvester and battery was evaluated for its ability to sustain the low‑power electronics required for the QD sensor and display functions.
Quantum‑dot layers were fabricated and characterized for electroluminescence and UV sensing. The QDs were integrated into a thin film that could be driven by the harvested power, providing both illumination for the watch face and a means to detect ambient UV levels. The system also included a small acoustic or mechanical signal output, controlled by the same electronics.
Throughout the project, the team considered environmental constraints such as temperature, humidity, and electromagnetic compatibility. The design had to accommodate the limited space of a watch case, the mechanical activation of the watch, and the need for low‑power operation. While basic functional tests confirmed that the energy level could be harvested and stored, the full watch demonstrator was not realized within the project timeframe due to the complexity of synchronizing multiple generators and integrating the QD layers into a compact form factor.
In summary, the MoNaUhr project achieved a proof‑of‑concept for a miniature energy‑harvesting system based on micro‑generators and an LTC3109 harvester, coupled with a solid‑state battery and quantum‑dot sensors. The collaboration between ADZ Nagano GmbH, the project leaders, and the funding agency enabled the exploration of novel materials and power‑management strategies, laying groundwork for future development of self‑powered wearable environmental sensors.